South Fork

Avalanche

Run Length

1558

Slab Width

320

Trigger Type

skier

Wind Exposure

crossLoadedSlope

Avalanche Size

4

Trigger Sub Type

intentional

Start Zone Aspect

S

Vegetation Cover

openSlope

Start Zone Incline

34

Avalanche Character

windSlab, persistentSlab, deepPersistentSlab

Crust Near Weak Layer

1

Number Of Avalanches

1

Start Zone Elevation

2300

Runout Zone Elevation

1479

Weak Layer Burial Date

2021-02-05T08:00:00.000Z

Avalanche Observation

24to48hrsAgo

Weak Layer Crystal Type

facets

Start Zone Elevation Band

alp

Avalanche Occurrence Datetime

2021-02-13T15:30:00

One rider watched from a safe point on the ridge as the other cautiously ski cut the top of a large, south aspect ,concave bowl. We expected a smallish wind slab might release, but the outcome was far greater. He was able to find the sweet spot and the wind slab cracked in weak, shallow snow near some krumholtz. The rider stopped and watched as the bowl crowned and spiderwebbed 10 metres below, zippering 320 metres across the concave slope. We watched in awe as the entire bowl roared down the mountain, stepping down and cleaning out all the buried persistent weak layers present in the snowpack. The avalanche widened the trim line in the path by 5-10 metres for the final 500 metres ,running full path and uphill on the opposing side of the valley. Once we collected our selves we crossed the bed surface and rode a treed ridge to valley bottom. The bed surface near the crown was facets on crust. We made a mistake stepping out too far for the uncertainty of the conditions. Had either of us been caught, it is extremely unlikely we would have survived. Fortunately our habits and actions mitigated what happened, and we were lucky.